Test 18 - Test Off-On Switch; Test 19 - Check Starter Motor - DeWalt DXGN4500 Manual

Section 3 Engine Diagnostic Tests
Remove all wires from START-RUN-STOP Switch
2.
(SW1).
Connect one meter lead to Terminal 2 and the
3.
other meter lead to Terminal 1. Actuate switch to
START position.
measured.
Actuate switch to the STOP position. INFINITY
4.
should be measured.
Keep one meter lead on Terminal 2 and connect
5.
the other meter lead to Terminal 3. Actuate switch
to the STOP position. CONTINUITY should be
measured.
Actuate switch to START position. INFINITY
6.
should be measured.
Connect one meter test lead to disconnected Wire
7.
0 from Terminal 2 and connect the other meter test
lead to the positive post of the battery, 12 VDC
should be measured. If voltage is not measured,
repair or replace Wire 13A between the starter
contactor and the START-RUN-STOP switch.
Connect all wires to the switch.
8.
Results
If any other readings were measured, replace
1.
START-RUN-STOP switch.
Refer to flow chart.
2.
Test 18 – Test OFF-ON Switch
General Theory
The OFF-ON switch applies a ground to the shutdown
harness (Wire 18). Applying ground to the harness
grounds out the magneto and inhibits spark.
Procedure
See Figure 3-3. Disconnect Point A from switch
1.
harness.
30
CONTINUITY should
Figure 3-3. OFF-ON Switch Test Points
Connect one meter lead to female side of
2.
connector and the other meter test lead to a clean
frame ground.
Actuate switch back and forth between ON and
3.
be OFF. CONTINUITY should only be measure in the
OFF position.
Results
If switch failed Step 3, replace OFF-ON switch.
1.
If OFF-ON switch is good, refer to flow chart.
2.
Test 19 – Check Starter Motor
The following
performance:
A binding or seizing in starter motor bearings.
1.
A shorted, open, or grounded armature.
2.
a. Shorted, armature (wire insulation worn and
wires touching),. indicated by low or no RPM.
b. Open armature (wire broken), indicated by low
or no RPM and excessive current draw.
c. Grounded armature (wire insulation worn and
wire touching armature lamination or shaft),
indicated by excessive current draw or no
RPM.
A defective starter motor switch.
3.
Broken, damaged or weak magnets.
4.
Starter drive dirty or binding.
5.
Procedure
The battery should have been previously checked and
fully charged.
Set a DMM to measure DC voltage (12 VDC). Connect
meter positive (+) test lead to starter contactor stud (the
small jumper wire connected to starter). Connect
common (-) test lead to starter motor frame (Figure 36).
Set Start-Stop Switch to START and observe meter.
Meter should indicate battery voltage. Starter motor
should operate and engine should crank.
conditions affect starter
Diagnostic Repair Manual
motor